Hydraulic mechanism



Dec. 1950 E. F. JIRSA EI'AL 2,533,466

HYDRAULIC MECHANISM Original Filed Nov. 5, 1945 7 Sheets-Sheet 1 30trl'fi n FIG. I

. 1N! 'ENTORS EMIL F. JlRSA MERLIN HANSEN CECIL w. BOPP ATTORNEYS Dec.12, 1950 E. F. JIRSA EI'AL HYDRAULIC MECHANISM Original Filed Nov. 5,1945 7 Sheets-Sheet 2 INVENTORS EMIL F. JIRSA MERLIN HANSEN BOPPATTORNEYS Dec. 12, 1950 E. F. JIRSA EI'AL HYDRAULIC MECHANISM '7Sheets-Sheet 3 Original Filed Nov. 5, 1945 INVENTORS EM" F. JIRSA MERLINHANSEN W. BOPP ATTORNEYS 7 Sheets-Sheet 5 Dec. 12, 1950 Original FiledNov. 5, 1945 HANSEN INVENTORS. MERLIN blL w. B0

ATTORNEYS EMIL F. JIRSA HE'S l2 Dec. 12, 1950 E. F. JIRSA ETAL 2,533,466

HYDRAULIC MECHANISM t Original Filed Nov. 5, 1945 '7 Sheets-Sheet 6 n6102 FIG. 4

111 2 :"':1 229 H: F3 223 4 a 282 69 270 240 l i 2 230 262 F FEE. l5 C;2e6

89 HO. 1M 'ENTORS. MIL F. JIRSAiMERLIN HANSEN BY r ECL w.

ATTORNEYS Dec. 12, 1950 E. F. JlRSA ETAL 2,533,466

HYDRAULIC MECHANISM Original Filed Nov. 5, 1945 7 Sheets-Sheet vINVENTORS. EMIL F. JIRSA MERLIN HANSEN a CECIL w. BOPP ATTORNEYSPatented Dec. 12, 1950 HYDRAULIC MECHANISM Emil F. Jirsa, Merlin Hansen,and Cecil W. Bopp, Waterloo, Iowa, assignors to Deere Manufacturing 00.,a corporation of Iowa Original application November 5, 1945, Serial No.626,626. Divided and this application February 12, 1947, Serial No.728,020

4 Claims.

The present invention relates generally to hydraulic apparatus and isparticularly well adapted for use in hydraulic control mechanism ontractors for raising, lowering, and adjusting implements mounted on thetractor or otherwise associated therewith, and has for its principalobject the provision of a novel and improved hydraulic control mechanismthat is more flexibly adapted to the various control requirements ofmodern implements. This application is a division of our copendingapplication, Serial No. 626,626, filed November 5, 1945.

Experience has indicated that for implements mounted directly upon atractor, the most desirable type of hydraulic control mechanism is thatwhich includes a control rockshaft mounted transversely at the rear ofthe tractor, with an actuating cylinder mounted inside of the housingand connected to the rockshaft by internal connections. It has also beenfound that the most convenient type of control for implements drawnbehind a tractor includes a portable hydraulic cylinder which can bequickly and easily mounted on the implement drawbar near the draftconnection to the tractor, with a flexible hose or hoses connecting thecylinder with the hydraulic control mechanism on the tractor.Heretofore, however, hydraulic control systems adapted for eitherrockshaft or remote cylinder control operations, involved considerabledifiiculties in converting the system from one type of operation to theother, in disconnecting the remote cylinder when the rockshaft was to beused and in looking out the integral cylinder when the remote cylinderwas to be used. Such prior systems required considerable time forinstructing untrained operators to properly attend to all of the varioussteps necessary in making a conversion.

One of the principal objects of the present invention, therefore, has todo with the provision of a hydraulic control system that is convertiblefrom rockshaft operation to remote cylinder operation with a minimum ofefiort and requiring very little instruction in familiarizing untrainedtractor operators with the procedure. In the accomplishment of thisobject, we have provided a system which can be converted from rockshaftoperation to remote cylinder operation simply by removing a pair ofplugs from the power control valve housing and inserting a pair of hosecoupling devices in place of the plugs. The hose coupling devices whichare inserted into the power control valve housing are in themselvesvalve elements which perform the function of making the required changein hydraulic duct connections, thereby eliminating the necessity for theoperator to open or close any valves in addition to the insertion of thehose coupling devices. Whereas two hose coupling connections arerequired for a remote cylinder of the double acting type in which fluidunder pressure can be supplied to either end of the cylinder, only onehose connection is required for cylinders of the single acting type, inwhich pressure is applied only to one side of the piston, and relyingupon gravity to return the piston to its initial position.

Heretofore, there has been a certain amount of danger connected with theuse of a remote cylinder to the draft member of an implement andconnected by flexible hoses to the power control mechanism of thetractor, for the reason that in case the draft connection between theimplement and the tractor breaks during operation, or in case theoperator disconnects the draft connection without dismounting thecontrol cylinder from the implement or disconnecting the flexible hoses,the entire draft force of the tractor will be transmitted through thehoses to the implement, which might either result in damage to theequipment or even in the overturning of the tractor. Therefore, it is afurther object of our invention to provide safety release means fordisconnecting the remote cylinder from the power control mechanismresponsive to the transmission of an excess tensional force through theflexible connecting hoses. In the accomplishment of this object, we haveprovided breakable elements'in the hose coupling, which are strongenough to securely hold the couplings during normal operation, but whichbreak apart to permit the coupling members to separate before asufficient force is transmitted through the hoses to cause any damage.The breakable elements are in the form of frangible washers, which arequickly and easily replaced after breakage.

These and other objects and advantages of our invention will be apparentto those skilled in the art after a consideration of the followindescription, in which reference is had to the drawings appended hereto,in which Figure 1 is a rear elevational view of a hydraulic controlmechanism mounted on the rear end of a tractor, showing a portion of therear axle housing of the tractor;

Figure 2 is a side elevational view of the hydraulic control mechanismshowing a double acting remote cylinder connected to the mechanism andalso showing the rockshaft housing and tractor axle housing cut away insection to expose the piston and cylinder and connections thereto;

Figure 3 is an elevational view looking rearwardly into the opening inthe front of the hydraulic control housing. as indicated by a line 3-3in Figure 2, and drawn to a larger scale;

Figure 4 is a sectional view taken along a line 4-4 in Figure 3;

Figure 5 is a sectional view taken along a line 5-5 in Figure 3;

Figure 6 is a sectional elevational view taken along a line 56 in Figure3;

Figure '7 is a sectional elevational view taken along a line 1-1 inFigure 3;

Figure 8 is an end view of the dual check valve, as viewed along a lineH in Figure 6; and drawn to a still larger scale;

Figure 9 is a sectional view taken along a line 0-5 in Figure 6 anddrawn to a larger scale;

Figure 10 is a sectional elevational view taken along a line Ill-l0 inFigure 3;

Figure 11 is a sectional plan view taken along a line I l-ll in Figure 1and drawn to a larger scale; a

Figure 12 is a. sectional elevational view taken along a line i2l2 inFigure 11 and drawn to an enlarged scale;

Figure 13 shows a portion of the sectional plan view of Figure 11 whichincludes the connector for the remote cylinder, but showing the hoseconnector replaced by a plug to condition the mechanism for controllingthe integral cylinder;

Figure 14 is a sectional bottom plan view taken along a line 14-14 inFigure 3;

Figure 15 is a top plan view showing the top of the hydraulic controlhousing with the top cover removed; and

Figure 16 is a sectional elevational view taken along a line Hil6 inFigure 1.

Referring now to the drawings, and more particularly to Figures 1 and 2,the tractor is indicated by a portion of its body including a. banjotype rear axle housing 20 comprising an enlarged centrally disposed gearhousing 2i and a pair of laterally extending axle housing quills 22formed integrally therewith. The quills 22 contain a pair of coaxiallydisposed drive axles 23. the inner ends of which carry drive gears 24,disposed within the gear housing portion 2| and the drive gears 24 aredriven from the engine of the tractor, the details of which are notshown since they are well known to those skilled in the art. The gearcompartment 2| of the axle housing 20 is provided with a large opening24' in the rear side thereof, which opening is covered by a largehousing or cover 25 having an outwardly turned flange 26 extendinperipherally around the housing 25 and secured to the gear compartment2| by bolts 21. The housing 25 is integrally formed with a transverselydisposed bearing sleeve 28 in the upper portion thereof, within which isjournaled a conventional rockshaft 29. the two ends 3| of which extendlaterally from the ends of the sleeve portion 28 and are ofsubstantially square cross section for the purpose of receivingimplement controlling and lifting arms (not shown), as is well known tothose skilled in the art.

The rockshaft 29 is actuated by a rocker arm 55. fixed to a hub 38secured to the rockshaft 29. The rocker arm extends downwardly and ispivotally connected by a pin 31 to a piston rod 38 (see Figure 7). Thepiston rod 38 extends forwardly and is connected to the piston 38 of afluid pressure motor 40 by means of a wrist pin 4|. The fluid pressuremotor 40 comprises the piston 39 and a cylinder 42. within which thepiston is slidable. A fluid supply duct 42 is formed integrally with thecylinder 42 and extends axially along the lower side thereof forsupplying fluid under pressure to the cylinder, the forward end of whichis closed by an integrally formed cylinder head 44. The cylinder 42 ispositioned between the two axle drive gears 24 and is secured to thefront side of the housing 25, the latter having a duct 45 formedintegrally therewith in register with the cylinder duct 43.

The construction so far described is identical with the hydraulicmechanism disclosed in Patent 2,302,637 granted November 17, 1942, toMcCormick and Hansen, to which reference may be had for more completedescription of this'part of the apparatus. As in the patented structure,the housing 25 also includes an integrally formed reservoir 46 for thehydraulic fluid and also a conventional gear pump indicated generally byreference numeral 41, which is secured by bolts 48 to the rear side ofthe housing 25. One of the pump gears (not shown) is mounted on thetractor power takeoff shaft 49. which extends rearwardly from a.suitable connection with the tractor engine and is journaled in a bearin50 beneath the reservoir 45 and formed integrally with the housing 25.The power takeoff shaft 4! extends rearwardly through the pump 41 andhas a splined rear end portion 5| for supplyin power to implementsassociated with the tractor. in a manner well known to those skilled inthe art. The pump 41 receives fluid from the reservoir 45 and dischargesthe same under pressure through a high pressure duct 52 extendingupwardly through the reservoir 46. as disclosed in the above mentionedpatent.

Coming now to that portion of the apparatus with which our invention isparticularly concerned. a control housing 50 is secured to the rear sideof the rockshaft housing 25 by means of a plurality of bolts 6i, whichextend through apertures 62 in the control housing 60 and engagesuitable threaded apertures (not shown) in the housing 25. The controlhousing 60 is provided with an opening 63 in its forward side, which isdisposed in register with a corresponding opening (not shown) in therear side of the housing 25. thereby communicating with the reservoir 45in the latter.

The control housing 50 is provided with a cored high pressure passage 64provided with an intake port 55, best shown in Figures 3 and 6, disposedin register with the upper end of the pump discharge passage 52. Thepassage 54 extends upwardly from the port 65 and turns rearwardly, asindicated at 66, Figure 6, to an enlarged port 51 in a verticallydisposed valve cylinder 68, within which is vertically slidable a valveplunger 69. The valve plunger 69 is provided with a centrally disposedpiston or spool 10 disposed within the annular port 61 and substantiallycoextensive therewith. The laterally opposite sides of the valve plunger69 and the upper edges of the piston 10 are ground off. as indicated atH, to provide flat portions of the valve plunger 58, along which thehydraulic fluid can flow. Similarly. the laterally opposite sides of thevalve plunger 59 below the piston 10, and the lower edge oi the latterare ground off, as indicated at 12, to provide passages for the flow ofhydraulic fluid. Hence. in the neutral or inactive position of theplunger 69, as shown in Figure 6. the fluid flowing upwardly through thepassage 64 and into the port 61 divides between the upper and lower flatportions 1|, 12 and flows therealong through the valve cylinder 68 to apair of upper and lower annular ports 13, 14, which communicate throughshort passages 15, 18, respectively, with the interior of the controlhousing 80, which in turn is in communication with the reservoir 48, asexplained above. The openings 15, 18 in th ports 13, 14 are best shownin Figure 3. Thus, when the control mechanism is inactive, the pump 41furnishes a continuous flow of hydraulic fluid, such as oil, upwardlythrough the passages 84, 88, and along the flats H, 12 to the ports 13,14, from which it flows through the openings 15, I8 back to thereservoir.

A pair of annular ports 11, 18 are spaced axially above and below thecentral inlet port 61 in the valve cylinder and these ports areconnected to a pair of rearwardl extending passages 19, 80,respectively, the rear ends of the latter being turned upwardly anddownwardly, respectively, and having valve seats 8|, 82 communicatingtherewith. Check valves 83, 84 are seated in the valve seats 8|, 82,respectively, and are of the poppet type and are of a special design,the details of which will be described later. The check valves 83, 84open into a pair of cylinder supply ducts 85, 88, which are curvedlaterally and inwardly of the housing 60 and intersect a pair ofcylindrical passages 81, 88 (Figsres 11, 14 and 16) which extendrearwardly and outwardly of the housing 60, and are adapted to receive apair of bayonet type connectors, indicated generally by referencenumerals 89, 90, fixed to the ends of a pair of flexible hoses 8|, 92attached to a double acting fluid pressure motor 83.

Each of the bayonet type connectors 89, 90 comprises a tubular memberI00, which is slidably insertable into the corresponding cylindricalpassage 81 or 88 and is provided with an axially extending opening IOItherethrough. The outer end of the tubular connector I is provided withan enlarged cylindrical head portion I02, the outer end of which has ahexagonal portion I03 adapted to receive a wrench for use in assemblingand disassembling the connector. The outer end of the aperture IOIthrough the connector I00 is enlarged, as indicated at I04 (see Figure11) the enlarged portion I04 being threaded to receive a bushing I05,within which is threaded a hose fitting I08, within which the associatedhose 9I or 92 is suitably fixed by means not forming a Part of thepresent invention.

Each of the connectors 89, 90 is adapted to be inserted into abayonet-receiving sleeve member H0, which is threaded to engage theenlarged outer end portion III of the passage 81, the portion I i Ibeing also threaded to secure the member I I 0 therein. An annularrecess I I2 is provided in the inner end of the sleeve IIO to receive anannular sealing member II3, which is held in compression by means of acoil spring H4 in engagement with the outer surface of the tubularmember I00, thereby preventing leakage of oil outwardly of the housing80 along the surface of the tubular member I00. The outer end of thesleeve I I0 has an enlarged bore, indicated at II5, which receives thehead portion I02, and the outer surface of the outer end of the sleeve II0 is threaded to receive a collar I IS, the latter being internallythreaded at II! to engage the threads on the sleeve I I0. The collar II8 is provided with an inwardly extending radial flange I I8, whichslidably embraces the head I02 of the connector I00. The head I02 isprovided with a peripherally extending groove II9, normally disposedsubstantially in radial alignment with the outer end 01' the sleeve H0and adapted to receive a. segmental washer I20, see Figures 11, 12 and13. The washer I 20 is substantially U-shaped, with inwardly extendingtangs I2I and is adapted to he slipped into the slot between the end ofthe sleeve I I0 and the inner surface of the flange I I8 of the collar8, so that when the latter is screwed tightly on the threaded sleeve IIOthe washer I20 prevents the bayonet connector I00 from slidingrearwardly out of the sleeve H0.

The connector I00 can easily be removed from the passage 81 and sleeveIIO by unscrewing the collar II8, after which the connecter I00 and itsassociated hose can be slipped rearwardly out of the sleeve.

The double acting fluid pressure motor 93 is adapted to be mounted onthe tongue or draft member of a trailing implement and comprises acylinder member I25, within which is slidably disposed a piston I28connected to a piston rod I21 having a connecting knuckle I28 mounted onthe outer end thereof and adapted to be coupled to the control elementor lifting lever of the trailing implement (not shown). The cylinder I25is provided with a cylinder head I29, which has an aperture I30 thereinto receive a mounting pin for mounting the cylinder on the tongue. Thehead I29 is provided with a hose fitting I 3|, to which the upperflexible hose 9I is connected, while the cylinder casting I25 isprovided with a cored passage I32 leading to the opposite end of thecylinder and provided with a fitting I33 to which the lower hose 92 isconnected.

Certain implements, such as plows, are fre quently equipped withreleasable draft connections, to permit the plow to become detached fromthe tractor when the plow encounters an immovable obstruction such as alarge stone or stump. In this event, it is especially desirable to havea releasable connection in each of the flexible hoses to prevent thelatter from being subjected to the full drawbar pull of the tractor. Toaccomplish this result, the segmental washer I20 is made of a relativelyeasily shearable substance, such as porous bronze, aluminum or softcopper, so that in case of failure of the implement draft connection,the tension in the hoses 9|, 92 will shear the tangs I2I of the washersbetween the inner edges of the grooves I I9 and the inner edges of theflanges II8 on the collars H6. After the implement has been reconnectedto the tractor, the hose connectors I00 can be reinserted into thesleeves H0 and secured by means of a new pair of segmental washers I20,although care must be taken to clean any dirt from the connectors I00before reinserting them into the passages 81. 88.

When it is desired to remove the remote cylinder 93 and operate theintegrally mounted fluid pressure motor 40, the connectors I00 arewithdrawn from the passages 81, 88 after their securing collars II8 havebeen unscrewed, and the connectors I00 are then replaced with solidplugs I3 (Figure 13), each of which is provided with a head portion I38of larger diameter, which is slidably received within the enlargedopening H5 in the outer end of the sleeve H0. The head I38 of the plugI35 serves as a handle by means of which the plug can be inserted andwithdrawn relative to the sleeve H0. The plug is secured in the sleeve II0 by means of the collar H8, the flange II8 of which engages a radialflange I 34 on the plug head I36. The shear washer I20 can be insertedin a groove I31 extending peripherally around the head I38 providedmerely for carrying the washer, as the latter is not needed when thecylinder 93 is not being used. Thus, the plug I35 extends through theseal II3, thereby preventing any leakage of oil out of the cylindricalpassage 81. The plug I35 is substantially the same length as theconnector I but is provided with a bore I45 in the end thereof extendingaxially and communicating with a diametrically extending opening I46 ina section of the plug of reduced diameter, the purpose of which will beexplained later. Hence, it will be evident that the plugs I35 areinterchangeable with the tubular connectors I00.

When the remote cylinder 93 is connected for operation, the plugs I35are stored in scabbards I38 (see Figures 1 and 2). Each of the scabbardsI38 comprises a tubular member having a closed end and an internallythreaded collar I39 adapted to cooperate with a threaded flange I40 (seeFigure 13) on the inner end of the head I36 of the plug. Each of thescabbards I38 is adapted to be inserted through a pair of verticallyaligned apertures in a sheet metal bracket I4I of U-shaped crosssection, which is secured by screws I42 to the side of the controlhousing The same scabbards I38 can be used to protect the tubularconnectors I00 when the remote cylinder 93 is not in use, at which timethe plugs I35 are disposed within the sleeves IIO. Each of the scabbardsI38 is long enough to receive the tubular connector I00, the latterhaving a threaded flange I43 (Figure 11) adapted to screw into theinternally threaded collar I39 around the open end of the scabbard. Ithas been found that with a little practice, an operator can readilywithdraw the tubular connector I00 from the sleeve IIO, slide in theplug I35, and secure the latter, and slip the scabbard I38 over thetubular connector and secure the same with no appreciable loss of oil.With the scab bards I38 protecting the tubular connectors I00, it isevident that the oil remaining within the cylinder and flexible hoseswill not be lost, while the scabbards also prevent dirt, water, or airfrom getting into the hoses.

The rear end of the passage 45 in the housing 25, for conveyinghydraulic fluid to and from the integral cylinder 42, is disposed inregister with a port I50 in the front side of the. control housing 60,best shown in Figure 14. The port I50 communicates with a passage I5I,the rear end of which turns upwardly and outwardly, as indicated at I52(Figures 3 and 7). The passage I52 communicates with an annular port I53in the cylindrical passage 88 which receives the lower hose connector90. The annular port I53 is disposed intermediate the ends of thecylindrical passage 88, so that when the tubular member I00 of the hoseconnector 90 is inserted within the passage 88, the outer surface of theconnector I00 blocks the port I 53 and passages I5I, I52, therebylocking the integral cylinder 42 against movement. An annular sealingdevice I54 (see Figures 14 and 16), prevents any flow of fluid betweenthe port I53 and the supply passage 86. However, it will be evident thatwhen the tubular member I00 is replaced by the plug I35, there is aconnection between the port I53 and the supply passage 86 through thebore I45 and opening I46 in the plug I35. The inner end portion of theplug holds the inner seal I54 in place.

A similar annular port I55 is disposed in the intermediate portion ofthe upper cylindrical passage 81, and this port communicates with theinterior of the housing 60 through an opening I56 in the top of the portI55, best shown in Figure 16. As indicated in Figures 11 and 16, whenthe tubular member I00 of the upper hose connector 89 is disposed inoperating position in the cylindrical passage 81, the port I55 isblocked and the fluid flows from the supply passage through theconnector I00 to the hose 9|. An annular sealing device I51 prevents anyleakage of oil along the outer surface of the tubular connector I00 andthrough the exhaust port I56. When the plug I35 is substituted for thehose connector 89, it is evident from Figure 13 that the supply passage85 is connected directly with the port I55 and exhaust opening I56through the bore I45 and opening I46 in the plug.

Referring now more particularly to Figures 2 and 14, a check valve .I60of the poppet type is seated in the port I50 and is urged toward seatedposition by means of a light compression spring I6I, which is supportedin a socket I62 in the housing 25. When the hydraulic fluid is forcedinto the cylinder 42 through the port I 53, and passages I52, I5I, 45and 43, the force of the oil opens the valve I60 to permit asubstantially free flow therethrough. However, when the piston 39returns toward the forward end of the cylinder 42, forcing the oil backthrough the passages to the reservoir, the valve I60 is returned by thespring I6I and by the force of the oil to a partially closed position asdetermined by a stop pin I63 disposed at the inner end of the stem I64of the valve I60. The pin I63 is disposed within an aperture I65, whichis threaded to receive a threaded portion I66 on the pin I63 forpurposes of adjusting the latter axially relative to the valve stem I64.A lock nut I61 engages the threaded portion I66 of the pin for thepurpose of locking the latter in adjusted position to determine theamount of opening around the valve I60, thereby determining the speedwith which the rockshaft returns from the raised position shown inFigure 2 to the lowered position under force of gravity exerted upon theload carried on the rockshaft 29. The outer end of the pin I63 isslotted, as indicated at I68, to receive a screwdriver for purposes ofadjustment and a cap I69 is provided for protecting the end of the pinin adjusted position and sealing against oil leakage along threads I66.The cap I09 is internally threaded to receive the threaded portion ofthe pin, which extends to the outer end of the latter. Details of thisvalve I60 and its operation are contained in the McCormick and Hansenpatent referred to above, and do not form a part of the presentinvention.

Referring now more particularly to Figures 6, 8, and 9, each of thecheck valves 83, 84 is a dual valve comprising an outer poppet valveI15, the stem of which is hollow and receives an inner poppet valve I16therein. The stem of the inner valve I16 fits closely but slidablywithin the passage I11 in the stem of the outer valve I15 and the innervalve seats in the outer end of the passage I11 in the head of the outervalve. The stem of the outer valve I15 is provided with three aperturesI18, I19, I80, spaced peripherally and extending radially incommunication with the passage I11. The stem of the inner valve I16 isprovided with an annular groove I8I under the head of the valve and isalso relieved along one side of the stem, as by grinding a flat portionI82 axially along the stem of the inner valve from the groove I8I toestablish communication with any one of the three apertures I18, I19,I80, selectively. The inner valve I16 can be rotated about the commonaxis of the two valves to place the fiat portion I82-in register withany of the apertures I 18, I19, I86, the latter being of relativelydifferent diam eters so that the resistance to the flow of oil throughthe inner valve can thus be adjusted. The two valves I15, I16 aresecured in angularly adjusted position by means of a locking washer I82,the latter having a non-circular aperture I83 therein which fits pver acorrespondingly shaped head I84 on the valve head. The locking washerI82 has a radially extending ear I85 which can be inserted into any ofthree notches I86 in an axially extending flange I81 encircling the headof the outer valve I15, the three notches I 86 corresponding to thepositions of registry of the three apertures I18, I19, I80,respectively. Each of the check valves 83, 84 is urged toward closedposition by means of a compression spring I88, which bears against thewasher I82 and reacts against a plug I89 screwed into a threaded openingI90 in" the outer end of the supply passage 86. A similar plug I89 isprovided for the other check valves 83 and screws into a similarthreaded opening I90 in the outer end of the passage 85.

Each of the check valves 83, 84 is actuated by means of a ball I 95disposed at the inner end of the valve stems, and the balls I95 bearagainst inclined grooves' I 96 in the valve plunger 69. The grooves I98are so inclined that when the valve plunger 69 is moved upwardly, theupper ball I95 is cammed outwardly against the upper check valve 83,while if the valve plunger 69 is moved downwardly within the valvecylinder 68 the lower ball I95 is forced outwardly to actuate the lowercheck valve 84. The length of the stems of the two coaxial valves issuch that the balls I95 engage the inner stems and open the inner valvesI18 before they engage the ends of thehollow stems of the outer valvesI15. This reduces appreciably the amount of effort necessary to open oneof the check valves, for if a single valve were to be used in place ofone of the dual valves, the

oil pressure against the large head would make than the area of a singlecheck valve that the total pressure is greatly reduced. After the innervalve has been cracked open, the pressure on the head of the outer valveis reduced sufllciently to make it comparatively easy to open. The ballsare thus used as tappets for opening the inner and outer check valves,sequentially, and eliminate a considerable amount of the friction andside thrust on the valve stems that would be involved if the inclinedcamming surfaces on the valve plunger directly contacted the valvestems.

The valve plunger 89 is provided with a pair of spools or pistons I91,I98 at its upper and lower ends thereof, respectively, the inner edgesof which are spaced outwardly from the inner edges of the annular ports13, 14, thus providing for a free flow of oil along the valve cylinder68 into the exhaust ports 13, 14, when the plunger is in its neutralposition. Moving the valve plunger 89 downwardly, however, moves theupper piston I91 into the upper end of the valve cylinder 68, therebyclosing off the upper reservoir port 13. Similarly, when the plunger 69is moved upwardly, the valve piston I98 acts against the upper edge ofthe port 14 to close the latter against flow of oil downwardly into thereservoir.

The operation of the mechanism thus far described, will now beexplained. To operate the rockshaft 29, it is first necessary todisconnect the remote cylinder 93 by unscrewing the threaded collars II8 and withdrawing the connectors 89, out of the passages 81, 88, afterwhich the plugs I35 are inserted into the sleeves H0 and secured bymeans of the shear washers I20 and collars I I8. The rockshaft 29 isactuated in a clockwise direction, as viewed in Figure 2, to raise theimplement associated therewith, this being accomplished by moving thevalve plunger 69 upwardly in the valve cylinder 68. The upward movementof the plunger 69 brings the lower piston portion I98 into closingrelation with the edge of the exhaust port 14 and simultaneously movesthe central piston portion 10 upwardly to cut oil the flow of oilupwardly through the valve cylinder 88. This flow is not reducedabruptly, however, in view of the fact that the edge of the pistonportion 10 is ground off on an arc 20I, with the result that the upwardflow of oil through the cylinder 68 is not entirely cut oil until thelowest point on the curved edge 20I coincides with the upper edge of thecentral port 61. During this gradual cutoff of the oil flow to thereservoir, the pressure increases in the high pressure duct 84 and inthe lower portion of the valve cylinder 88 beneath the inlet port 81.This causes the oil to flow along the flat portion 12 of the valveplunger 69 and through the port 18 and passage 80, thereby forcing thecheck valve 84 away from its seat 82 against the pressure of the springI88 (Figure 6). The oil then fiows through the supply duct 86 andthrough the passage 88 (Figure 14), but inasmuch as the latter isblocked by the plug I35, the oil flows into the port I53 through thebore I45 and port I46 in the plug and along the passages I52, I5Ithrough the port I50. The oil pressure forces the valve I60 open againstthe pressure of the light spring I6I and then enters the forward end ofthe cyl inder 42 through the ducts 45, 43, causing the piston 89 to moverearwardly in the cylinder. The upward movement of the valve plunger 69has also forced the inclined surface of the groove I96 against the ballI to open the upper check valve 83, but there is no flow of oil throughthis valve at this time, after the edge 20I moves into register with theupper edge of the port 81.

The movement of the piston 39 in the cylinder 42 can be interrupted atany point within its range by merely returning the valve plunger 69 tothe neutral position shown in Figure 6, whereupon the oil supplied bythe pump is again exhausted to the reservoir through the upper and lowerexhaust ports 13, 14. The check valve 84 then closes, thereby lockingthe oil within the cylinder 42 and the passages connected there with.

The piston 39 can be returned toward the closed end of the cylinder 42by moving the valve plunger 69 downwardly in the valve cylinder 88 fromthe neutral position. Assuming that there is an implement load on therockshaft 29, tending to rotate the latter in a counterclockwisedirection, as viewed in Figure 2, it will be evident that there is anappreciable pressure built up by the piston 39 against the oil which islocked within the cylinder 42 by the lower check valve 84. Thus, it willbe evident that by opening the check valve 84, the oil trapped in thecylinder 42 will be forced outwardly through the valve seat 82. therebypermitting the piston to move toward the closed end of the cylinder andallowing the rockshaft to move in a counterclockwise direction to lowerthe implement. Accordingly, the

assasoe first movement of the plunger 69 downwardly in the valvecylinder 66 cams the valve actuating ball I96 against the end of thevalve stem of the inner poppet valve I 16, permitting the oil to flowfrom the supply passage 66 under the head of the inner valve I16 andalong the release passage I32, and out through the aperture I19 andthrough the passage 30 to the port 19, then downwardly through the valvecylinder 63 to the reservoir port 14. As the plunger 69 moves downwardlyin the cylinder 63, the oil from the pump flows upwardly into the upperportion of the valve cylinder 63, but inasmuch as the upper spool orpiston I91 closes the reservoir port 13, the oil leaves the valvecylinder 68 through the port 11, passage 19, and valve seat lI, into theupper supply passage 33, and then through the passage 31 into theintermediate port I66, and since the plug I36 closes the outer end ofthe passage 31, the oil flows upwardly through the exhaust port I66 andreturns to the reservoir (Fi ure 16).

It will be noted that the speed of travel of the piston 39 forwardly inthe cylinder 42 is dependent first on the amount of open ng under thevalve I66 as determined by the adjustable pin I63 and second. by thesize of the aperture I13 in the hollow stem of the outer check valveI16, which restricts the flow of oil under the head of the inner valveI16. However, by moving the valve plunger 69 downwardly to its extremeposition, the ball I96 engages the end of the hollow stem of the outervalve I16 and opens the latter, thereby allowing the oil to flow throughthe seat 62 as well as through the inner seat, thereby causing thepiston to move at a greater rate in the cylinder 42. It is also evidentthat the speed of travel of the piston can also be controlled byinfinitesimal increments by shifting the valve plunger 69 in the valvecylinder 63. thereby adjusting the amount of openin: under the heads ofthe inner and outer check valves I16, I16.

Provision is also made for adjusting the speed of travel of the piston39 rearwardly in the cylinder 42 to adjust the speed of raising movementof the rockshaft 29 in a clockwise direction, as viewed in Figure 2.Referring more particularly to Figures 3 to 6, inclusive, it will benoted that a drilled passage 206 extends upwardly from the a bottom ofthe control housing 60, the lower end of th s passage being closed by aplug 206. This passage intersects the horizontal portion 66 of the highpressure duct 64 and continues upwardly to intersect a horizontalpassage 201, which extends inwardly from the side of the control housing60. The passage 201 intersects a second horizontal passage 200, whichextends rearwardly from the front side of the housing 60, the opening ofthe passage 203 being closed by a plug 209. The passage 206 communicateswith a port 2I0 in the valve cylinder 63 above the inlet port 61. Thevalve plunger 69 is reduced in diameter in front of the port 2I0 asindicated at d to provide for flow of oil from the latter to the flat 1Iand thus to the reservoir port I3. The passage 201 is provided with anannular valve seat 2, which cooperates with a valve member 2I2 in theform or a pin having a threaded portion 2I3 which engages internalthreads in the passage 201. The outer end of the pin is provided with aslot 2I4 adapted to receive a screwdriver for adjusting the valve 2 I2toward and away from the seat 2| I, for increasing or decreasing theresistance to the flow of 12 oil which is lay-passed from the inletpassage 66 to the valve-cylinder 66. The purpose of this by-pass orbleeder duct 205, 201, 208, 2I0 is to by-pass a portion of the oilsupplied through the duct 64 after the valve plunger 69 has been raisedto the point in which the cutoff edge 20I has closed the upper edge ofthe inlet port 61, thereby reducing the speed of travel of the piston 39rearwardly in the cylinder 42 during the rais ing operation. Thisbleeder port 2I0, however, is gradually cut oif by the piston portion 10of the valve plunger as the latter is raised in the cylinder 68, untilin extreme upper position, the bleeder port 2I0 is entirely closed,thereby providing for maximum speed of movement of the piston 39. Thus,the speed of raising movement of the piston can be adjusted by adjustingthe valve 2I2 toward or away from the seat 2 I I, and a lock nut 2I5 isprovided for securing the valve 2I2 in adjusted position. A cap 2I6 isprovided for protecting the outer end of the valve pin 2. This valve 2I2should preferably be closed when the control mechanism is used inconnection with a remote cylinder 93 of the double acting type, as willbe seen later.

The valve mechanism can be used to control a remote cylinder of thesingle acting type in which the fluid is supplied to only one end of thepiston, relying upon the force of gravity other means for returning thepiston to the closed end of the cylinder, without any preparation otherthan to remove the lower plug I36 from the lower cylindrical passage 86and replace it with a hose connector 90 connected to the single flexiblehose 92 leading to the single acting remote cylinder (not shown). Theoperation with this type of remote cylinder is similar to that describedin connection with the single acting integral cylinder 42, except thatthe oil is forced from the supply passage 66 through the tubularconnector I00 and through the flexible hose 92 to the remote cylinder,while the port I63 leading to the integral cylinder 42 is blocked by thetubular member I00, as indicated in Figure 16. The upper plug I35 isleft in place, thereby exhausting the upper supply passage 85 throughthe port I56 to the reservoir as before.

The operation of the mechanism in connection with a double acting remotecylinder 93 will now be described. As in the case of the integralcylinder 40, the double acting remote cylinder 93 is extended in a powerstroke by movin the valve plunger 69 upwardly in the valve cylinder 68.This directs the flow of oil from the pump passage 64 downwardly throughthe cylinder 68 and through the lower check valve 84, the lower hoseconnector 90, and the flexible hose 92 to the head end of the remotecylinder 93, thereby causing the piston I26 and piston rod I21 to moveoutwardly in the cylinder casting I25. The oil on the outer side of thepiston I26 is forced by the latter through the duct I32 and fittingI33'to the flexible hose 9i, which leads the oil through the upper hoseconnector 89 and tubular member I00 to the upper supply passage 85. Inthe raised position of the plunger 69 the inclined camming groove I96forces the ball I95 outwardly, thereby opening the inner valve I16 topermit the oil to flow through the seat and along the relieved portionI82 to one of the apertures I18, I19, I60 in the check valve 83. Bymoving the valve plunger 69 farther upward, the ball I95 engages thetubular stem of the valve 63 and lifts the valve head from the seat 8|,thereby obtaining a freer flow of oil therethrough, from which the oilflows through the passage 19 and along the flat portions 1| of theplunger into the reservoir port 13.

As stated above, it is preferable to close the bleeder valve 2I2 againstits seat 2 when the double acting remote cylinder is used, for theresistance of the small apertures I18, I19 or I80 results in a reducedspeed of operation of the piston I26 in the cylinder I25 unless theplunger 69 is moved upwardly to its extreme position. However, inasmuchas no more oil can flow into one end of the cylinder I25 than flows outthe other end, there will be a surplus of oil supplied by the pump whenthe double acting hydraulic motor 93 is operatedat that reduced speed.This oil surplus is exhausted to the reservoir through an excesspressure relief valve which will be described later.

The piston I26 is returned by hydraulic power to the head end of thecylinder I25 by shifting the valve plunger 69 downwardly from itsneutral position until the curved edge 202 of the relieved portion 12 onthe valve plunger 69 moves into blocking position at the lower edge ofthe port 61, thereby preventing the oil from flowing downwardly throughthe valve cylinder 68, whereupon all of the oil from the duct 64 flowsupwardly through the cylinder 68 and along the flat sides 1i of theplunger. The spool I91 at the upper end of the plunger has now movedinto clos ng relation in the top of the cylinder 68, closing off thereservoir port 13, and directing the oil through the port 11, passage19, and seat 8i to force open the upper check valve 83. The oil thenflows through the upper supply passage 85, through the connector 89 andflexible hose 9| to the cylinder passage I32, from which it flows intothe outer end of the cylinder I25 and forces the piston i26 toward thehead of the cylinder. The speed of piston movement in this direction isgoverned, during the first portion of downward movement of the plunger69, by the size of the aperture I18, I19 or I80, which is disposed inregister with the relieved portion I82 on the inner stem of the lowercheck valve 84. Here again, the surplus oil supplied through the duct 64by the pump must be relieved through an excess pressure relief valve aswill be described later.

The lower end of the valve cylinder 68 is threaded as indicated at 229,to receive a plug 22I in the bottom of the housing 60. The plunger 69can be removed from the cylinder 68 downwardly through the threadedaperture 220 after the plug 22I has been removed. The upper end of theplunger 69 is provided with an upstanding ear 225 (see Figures 3 and 6),which is connected by a short link 226 to an arm 221 cast integral ywith a hub 228 rigidl fixed on a control rockshaft 229, which isJ'ournaled in a pair of bearing bosses 230, which are integral with thesides of the control housing 60. A control lever 23I is mounted on a hub232, which can be mounted on either end of the rockshaft 229, the latterextending laterally out of the housing 60 for this purpose. A key 233 isprov ded between the rockshaft 229 and the hub 232 for preventingrelative rotation therebetween. In Figure l the lever 231i is shown insolid lines in mounted position on the left end of the shaft 229 and indotted lines is shown the alternative position of the lever on the otherend of the shaft.

Thus it is evident that with the lever 23I extending upwardly in asubstantially vertical position, although inclined slightly in atransverse 14 direction, the valve plunger 69 is in its intermediate orneutral position shown in Figure 6. The valve plunger 69 is raised byswinging the lever 23I forwardly, thereby rocking the rockshaft 229 in acounterclockwise direction, as viewed in Figure 6. Conversely, byswinging the lever 21 rearwardly from the neutral position, the valveplunger 69 is lowered from its neutral position. The limit of downwardmovement of the valve lunger is determined by the engagement of thelower end of the plunger with the plug MI. The upper limit of movementof the plunger 69 is limited by means of an adjustable limit stop com--prising a bolt 235 extending through a suitably threaded aperture in anarm 236, formed integrally with the hub 228 and plunger actuating arm221. The threaded endof the bolt 235 engages a shoulder 231 in the topof the housing 60, which defines the edge of a top opening in thelatter, and the bolt 235 is so adjusted that when it engages theshoulder 231 the'piston portion 18 of the plunger 69 covers the port 2III in the bieeder duct 208.

A look nut 238 is provided on the bolt 235 for locking the latter inadjusted position.

A cover plate 239 closes the opening defined by the shoulder 231 in thetop of the housing 60 and is secured in place by a pair of screws 240.

The valve plunger 69 is yieldably retained in neutral position by meansof a centering arm 245, which is swingably mounted on a transverse shaft246, the latter being carried between two bearing supports 241 in thehousing 68 (see Figures 10 and 11). The arm 245 carries a rol er 248journaled on a pin 249 between a pair of legs 250 formed integrally withthe arm 245. The roller 248 bears on the edge of a cam 251, which isformed inroller supporting legs 250 on the arm 245.

tegrally with a hub 252 rigidly clamped to'- the control rockshaft 229to rock therewith. The outer edge of the cam 25I is provided with adepression 253, which receives the roller 248 when the rockshaft 229 ispositioned to set the valve plunger 69 in its neutral position. Theroller 248 is urged into the depression 253 by means of a helicalcompression spring 255, which bears against an arm 256 extendingoutwardly of the The other end of the spring 255 is received within arecess 251 in the housing casting 69. The sides of the recess 253 areinclined in outwardly converging manner, so that the pressure of theroller 248 against the sides of the recess 253 tends to center therockshaft 229, the control lever 23I, and the valve plunger 69 by actionof the spring 255.

It is desirab e that the operator be able to feel that point in themovement of the control lever 23I when the valve plunger 69 is in itslow speed operating position, with the inner check valve member'I16 openbut with the outer check valve I15 closed, and with the cutoif edge 2Mor 202 of the piston member 18 in register with the corresponding edgeof the inlet port 61. This is pro vided for in each direction ofmovement of the control lever 23I by means of a pair of camming p ates260, 26I, which are slidaby disposed in slots 262 in the camming edge ofthe cam 25I on either side of the recess 253 (see Figures 3, 10 and 15).Each of the camming plates 260, 26I is secured within the slot 262 bymeans of a bolt 263, which passes through an elongated slot 264 in theplate to permit each of the plates to be adusted toward and away fromthe central recess 253 in the cam. Each of the camming plates 260, 26Iis provided with a beveled edge 265, which is adapted accuse to engagethe roller 243 when the rockshaft 228 is rocked to raise or lower thevalve plunger 83 from its neutral position to the low speed operatingposition mentioned above. Thus, when the operator feels the resistanceof the lever to further movement in either direction, he knows that theroller 248 has engaged the camming shoulder a 265 and therefore thefluid motor is moving at its maximum speed in the lower range ofoperation. However, by moving the control lever 3| still further, theshoulder 265 acts to depress the roller 248 and arm 245 against thecompression of the spring 255. This requires a little more effortexerted against the control lever 23l, telling the operator that thevalve plunger 69 is in the higher speed range of operation of the fluidmotor, and has raised the outer check valve member I15 from its seat. Atany time, the operator can let go of the lever 23 i, and the force ofthe compression spring 255 acting through the roller 248 will swing therockshaft 229 and lever 23l back to its neutral position.

When the operator is making an adjustment of the implement by means ofthe hydraulic mechanism, it is of course necessary for the operator tomanipulate the control lever 23I to make the necessary adjustment.However, when the operator desires a full stroke operation of the fluidmotor piston in its cylinder, such as when raising an implement to thetransport position or dropping it to an extreme lowered position, it isdesirable that the lever may be simply swung to its extreme position ineither direction, selectively, and released by the operator without thenecessity for holding it in operating position until the fluid motor hascompleted its stroke. For example, when operating a cultivator or plow,the operator must raise the implement and immediately turn the tractorwhen he comes to the end of the row or furrow, and it would beinconvenient for him to hod the operating lever in its raised positionuntil the implement is fully raised. Therefore, a detent mechanism isprovided for retaining the lever in either extreme position and forautomatically releasing the lever and return ng it to neutral positionas soon as the fluid motor has reached the end of its stroke.

Referring now more parti ularly to Figures 3, '7 and 15, a rearwardlyextending latching plate 218 is formed integrally with the hub 252, thelatter being split axially, as indicated at 21 I, and provided with apair of clamping lugs 212 clamped together by a bolt 213 to secure thehub 252 rigidly on the rockshaft 228. The plate 218 is provided with anarcuate edge 214, which is curved about the axis of the controlrcckshaft 229 in a circular arc. The surface 214 is engaged by a roller215, which is journaled on a pin 216 in one arm 211 of a bell crank,having a hub 218 mounted on a shaft 219, the latter being disposedtransversely in the housing 88 and supported in one wall thereof and ina lu-g 288. The other arm 28i of the bell crank is pivotally connectedby a pin 282 to a rod 283, which extends vertically downwardly through acylindrical passage 284 in the housing casting 68. The lower end of thebolt 283 is riveted to a. washer 285 against which bears the lower endof a compression spring 286. The upper end of the spring 286 reactsagainst a plate 281 which has a central aperture 288 through which thevertical rod 283 passes and the plate 281 is secured by screws 289 atthe upper end of the cylindrical passage 284. The spring 286 is stressedin compression to urge the rod 233 downwardly, thereby swinging the bellcrank arms 211, "I in a clockwise direction, as viewed in Figure 7, andthereby urging the roller 213 against the curved surface 214. The roller215 has no effect upon'the rockshaft 228 during the intermediate portionof the stroke of the control lever 23I inasmuch as the surface 214 is acircular arc about the axis of the shaft 229. The edge of the cammingplate 218, however, is beveled oif sharply at the upper and lowercorners, as in-- dicated by reference numerals 29l, 292. When thecontrol lever 23! is swung to its extreme position in either direction,the roller 215 engages one of the beveled comers 29L 292 and latches theplate 218 in this position, holding the rockshaft 229 and control lever23l against the action of the centering roller 248, thereby causing thefluid pressure motor to be extended to the end of its operating stroke.At the end of its stroke, the piston of the fluid pressure motor engagesa stop which prevents any further extension. This causes the pressure ofthe fluid in the cylinder to rise to a value appreciably in excess ofthe pressure necessary to actuate the load, and this excess pressure isused to return the valve plunger 33 to its neutral position, as will beexplained. When the piston 38 in the integral cylinder 42 reaches theend of its working stroke, as shown in Figure 2, the rear end of thepiston rod 38 engages a boss 293 (Figures 3 and 7), formed integrallywith thediousing casting 88.

The excess pressure relief valve, mentioned above, is best shown inFigure 4, and comprises a sleeve type valve 388 having a hollow stem 3,which fits slidably within a passage 382 which communicates with thehigh pressure duct 84 through a drilled passage 383, which extendsinwardly and upwardly from one side of the housing 68, the outer end ofthe passage being enclosed by a plug 384. A short duct 385 connects thedrilled passage 383 with the pump discharge duct 64. The duct 385 isalso drilled from the front of the housing through the duct 64, and theouter end of the passage is blocked by a plug 386. Thus, the oil canflow from the pump discharge duct 64 through the interconnecting passage385 through the drilled passage 383 to the excess pressure relief valveport 382. Incidentally, the drilled passage 383 also intersects thevertical bleeder passage 285, which extends upwardly through thehorizontal portion 86 of the pump discharge passage. The head cf thevalve member 388 is seated in the end of the short passage 382 and isdisposed within an enlarged valve chamber 381. A strong compressionspring 388 holds the valve 388 in closed position against all normaloperating pressures. The spring 383 is disposed within a cylindricalpassage 3", which extends inwardly from the rear of the chamber and isclosed by a plug 3| i. The hollow stem 38! of the valve 388 is providedwith radially extending apertures 3l2, which communicate with the valvechamber 381 when the valve 388 is forced by an excess pressure of oilagainst the spring 388. This relieves the oil from the pump dischargepassage 64 through the passages 385, 383 and through the inside of thestem 381 and out through the radial apertures 3l2 into the valve chamber381. The valve chamber 381 intersects the vertical cylindrical passage284 underneath the washer 285 on the rod 283. A kickofl' plunger 3l5 isslidably disposed in the lower portion of the cylindrical passage 284and is provided with an intermediate portion of reduced diameter 3l6,around which the oil flows assacee from the valve chamber 381. The lowerend of the kickofl plunger 3I5 is provided with an axially upwardlyextending recess 3I1, which is con-- sage 284 flows through theapertures 3I8 into the recess 8| 1 and acts upon the plunger 3I5 toforce the latter upwardly into engagement with the washer 285 and pushesthe latter and the rod 283 upwardly, thereby swinging the bell crankarms 211, 28I in a counterclockwise direction, as viewed in Figure 7,about the supportingshaft 219, thereby lifting the roller 215 out ofengagement with the beveled comer 29I or 282. The passage 284 isprovided with an annular groove 328, which is connected in communicationwith the reservoir through a port 32I. Thus, when the edge 323 on theplunger 3I5 along the upper end of the portion 3I6 of reduced diametermoves upwardly beyond the lower edge of the annular groove 328, the oilwithin the passage 284 is ex-- hausted through the groove 328 andaperture 32I to the reservoir. A small hole 322 is provided in thehousing casting below the aperture 32I to relieve the pressure in thecylindrical passage 284 to permit the oil in the passage to escape afterthe valve plunger 69 has been returned to its neutral position. As soonas the roller 215 is lifted out of engagement with the beveled corner28I or 292, the pressure of the spring 255 acting against the roller248, forces the latter against the inclined edges of the recess 253,thereby returning the rockshaft 229 and control lever 23I to neutralposition from either extreme position of operation.

Hydraulic fluid is supplied to the reservoir 46 through a fitting 325,which is screwed into a threaded aperture 326 in the rear side of thehousing 68, best shown in Figure 10. The fitting 325 is provided with acap 321 which normally closes the fitting 325. A petcock 328 is providedin the side of the housing 68 at the preferred level of the liquid inthe housing. When the operator is replenishing the liquid in thereservoir 46, he opens the petcock 328 and fills the resservoir untilthe fluid flows out of the petcock 328, after which the latter is closedtightly and the mechanism is ready for operation.

The operation of the power control mechanism will now be brieflysummarized. When the operator wishes to extend the fluid pressure motor,thereby raising the implement, he moves the operating lever 23Iforwardly, and if he wishes to lower the implement he moves the lever23I rearwardly from its vertical neutral position. When it is desired tomake a minor adjustment in the position of the implement, the lever 23Imay be moved only a small distance to cause the piston of the motor tomove slowly in the desired direction, and the farther the lever is movedthe faster will be the movement of the piston in its cylinder. When theoperator feels the resistance to the actuation of the control lever 23Iprovided by the roller 248 engaging the camming plate 268 or 26I, heknows that the piston is moving at its maximum speed in the low speedrange of operation, as determined by the setting of the bleeder valve2I2 in the case of a single acting cylinder or by the size of theaperture I18, I19 or I88 in the dual check valve when operating a doubleacting remote cylinder. The speed of lowering the implement in the caseof the single acting integral cylinder is also controlled by the settingof the check valve I 68 by means of the adjusting pin I63. The highspeed range of adjustment of the fluid pressure motor'is obtained bymoving the lever 23I against the action of the roller 248 climbing overthe inclined shoulders 265 of the camming plates 268, 26I, and thefarther the lever 23I is moved, the greater the opening under theoutercheck valve I15, and hence the greater the speed of operation ofthe fluid pressure motor.

The movement of the motor can be stopped at any time by the operatorreleasing the control lever 23I which will be centered by the action ofthe spring 255 acting through the roller 248 and recess 253 in the yokeI, but when the lever 23I is swung to its extreme position in eitherdirection, it is yieldingly latched in that position by the roller 215engaging the beveled corner 29I or 282 of the latching plate 218. Whenthe fluid pressure motor reaches the end of a power stroke, theincreased pressure of the fluid within the cyl=- inder acts through thekickoff plunger 315 torelease the roller 215 from the latching plate218,

whereupon the lever is automatically returned to neutral position by theactionof the compres-" sion spring 255 and the centering roller 248. Acase of a double acting cylinder, the kickofi' plunger will operate toreturn the control lever 23I from either extreme position of operation,

since the piston I26 moves in both directions under oil pressure;However, when a single acting cylinder is used, it moves under oilpressure only in one direction but is returned in the other direction bythe weight of the implement and there is no fluid pressure available toactuate the kickof! plunger 8I5, hence the control lever 23I remainslatched in the lowered position after the implement has been lowered anduntil the operator releases the lever manually. There is no necessityfor the operator to return the lever to neutral, but it may be left inthe extreme lowered position until he is ready to again raise theimplement.

It should be pointed out that when the control lever 23I is swung to thelatched position to effect a power stroke of the fluid pressure motor,the lever will be returned to the neutral position to relieve thepressure from the system in case the load exceeds the pressure of thespring 388 at any time during the stroke and not necessarily the end ofthe stroke. Hence, in case the implement encounters an obstructionduring its adjustment, the valve plunger 68 will be returned to neutralposition immediately, thereby waming the operator of the obstruction andrelieving the fluid pressure in the system We do not intend ourinvention tobe limited to the exact details shown and described herein,except as limited by the claims which follow.

We claim:

1. In hydraulic mechanism, the combination of a fluid pump, a pair offluid pressure motors, one of said motors comprising a single actingcylinder having a piston-slidable therein and a fluid connectionat oneend of the cylinder, the other of said motors comprising a double actingcylinder having a piston slidable therein and fluid connections withboth ends of said cylinder, control mechanism therefor including ahousing having a pair of cylinder supply ducts therein and a pair ofpassages intersecting said ducts, respectively, and extending therefromoutwardly of said housing, a port in each of said passages intermediatethe ends thereof, and a, fluid reservoir, one of said portscommunicating with said reservoir and means connecting the other of saidports with said single acting cylinder, valve means for directing fluidfrom said pump to either of said supply ducts, selectively, andcoincidentally directing fluid from the other of said supply ducts tosaid reservoir, and means for optionally connecting the two ends of saiddouble acting cylinder to said supply ducts, respectively, insubstitution for said single acting cylinder comprising a pair oftubular connectors connected with said two ends, respectively, andinsertable into said passages to points inwardly of said ports, theouter surfaces of said connectors being cooperative with said passagesto close said ports, and means for optionally closing the outer ends ofsaid passages after said connectors are withdrawn to establishcommunication through said passages between each of said supply ductsand the port associated therewith.

2. In a hydraulic system: a casing; means providing a cylindrical,fluid-transmitting bore within the casing that extends axially outwardlyand opens at the exterior of the casing to provide an outer port; meanswithin the casing providing first and second, separatefluid-transmitting ducts communicating with the bore at junctions spacedaxially apart as respects the axis of the bore, the first duct junctionbeing relatively remote from the outer port of the bore and the secondduct junction being relatively closer to said outer port; and meansincluding a coupler having a cylindrical tubular portion axiallyreceivable by and axially removable from the bore from outside thecasing, said tubular portion including an annular wall of suflflcientaxial length to extend into the bore past and in fluid-blocking relationto the second duct junction, and having an inner open end portioncommunicable through the first duct junction with said first duct, saidannular wall being imperforate so as to block said second duct junctionirrespective of variations in angular positioning of the tubular portionin said bore, said coupler having an open outer end communicatingthrough the tubular portion with said open inner end.

3. In a hydraulic system: a casing; means providing a cylindrical,fluid-transmitting bore within the casing that extends axially outwardlyand opens at the exterior of the casing to provide an outer port; meanswithin the casing providing a pair of separate fluid-transmitting ductscommunicating with the bore at junctions spaced axially apart asrespects the axis of the bore, one 01' said duct junctions beingrelatively remote from the outer port of the bore and the other ductjunction being relatively closer to said outer port; and means includinga coupler having a cylindrical tubular portion axially receivable by andaxially removable from the bore from outside the casing, said tubularportion being of suflicient axial length to extend into the bore pastthe relatively closer duct junction and toward the relatively remoteduct junction, and further being annularly imperforate adjacent one ductjunction and having a port adjacent the other duct junction soconstructed and arranged as to block 011 one duct and to communicatewith the other irrespective of any variation in angular positioning oi.the coupler as respects the bore. said coupler having an outer open endcommunicating through the tubular portion with said tubular portionport.

4. In a tractor equipped with a hydraulic system including a pump and afirst motor built into the tractor to form integral part thereof andadapted for use with a second motor disconnectibly associated with thetractor and structurally external to the hydraulic system and having aconduit for connection to the system, the improvement residing in acommon valve unit for operating the system with either the first orsecond 'motors, comprising: a casing mountable on the tractor and havinga highpressure passage communicable with the pump and outlet passagemeans communicable selectively with either motor, said outlet passagemeans including a bore opening at one end portion to the high-pressurepassage and opening at its other end exteriorly of the casing to providea second-motor port, and a first-motor port within the casing opening tothe bore and leading to the built-in first motor; removable portblockingmeans carried by the casing for blocking the second-motor port whileleaving the highpressure passage and first-motor port in communicationvia the bore, said means being externally removable to open saidsecond-motor port; and a conduit coupler connected to the second-motorconduit and connectible to the second-motor port after removal of saidport-blocking means. and having a conduit shank axially receivable byand capable of being axially withdrawn from the outlet passage bore,said shank having a port-blocking portion effected when the coupler isreceived in said bore to block oflf the first-motor port and furtherhaving a passage opening to the high-pressur passage, whereby saidhigh-pressure passage is cut off from the first motor and is connectedto the second motor.

EMIL F. JIRSA. MERLIN HANSEN. CECIL W. BOPP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 661,352 Moody Nov. 6, 19001,177,476 Bresse Mar. 28, 1916 1,931,8 5 Conley Oct. 24, 1933 2,226,192Barrett Dec. 24, 1940 2,292,961 Mott, Aug. 11, 1942 2,379,536 MackenzieJuly 3, 1945 2,416,373 Brown Feb. 25, 1947 2,430,696 Acton Nov. 11, 1947

